OCG Rulings

"Kasha" is a Special Summon monster. *This card cannot be Special Summoned, except by the method written on the card. It cannot be Special Summoned from the Graveyard, etc, with another card effect.[2]

The effect of "is the number of Zombie-Type monsters returned to the Deck by this card's effect x 1000." resolves as part of the effect which returns all monsters other than "Kasha" to the Deck. It does not start another Chain.[2]

If a non-Zombie-Type monster's Type is changed to "Zombie" by the effect of "DNA Surgery" and is returned to the Deck by the effect of "Kasha", then it is not counted as a Zombie-Type monster being returned to the Deck. The ATK of "Kasha" will be 1000x the number of monsters returned to the Deck whose Types were originally "Zombie".[3]

The ATK of "Kasha" is determined by the number of returned monsters which are Zombie-Type while they are in the Deck. If "Zoma the Spirit" is returned to the Deck, it is not a Zombie-Type monster while in the Deck, so it is not counted. Token Monsters are not returned to the Deck, so they will not be counted.[4]

The ATK of "Kasha" is equal to 1000x the number of face-upZombie-Type monsters which were returned from the field to the Deck. Thus, if a face-down Zombie-Type monster is returned to the Deck, then it is not counted as a Zombie-Type monster being returned to the Deck by the effect of "Kasha".[6]